(UPDATE: So I had a feeling that the idea below was a non-starter, but I never let that shut my mouth before so I figured why not post it anyway. But after several tests, sadly, it's not really all that fun, for reasons noted at the bottom of this post. Fortunately, Isaac James has a pretty neat little Barbarians variant he posted in response to this, check it out here.)

Here's a variant for Carcassonne that doesn't require any meeples, just your tiles from the basic set. The theme is that you're building Carcassonne and then thousands of years later exploring the ruins of the city, hoping to be the discover to expose the ancient cities, roads, cloisters, and farms.

Phase 1: Rise
On your turn, draw a tile from the bag and place it on the play area according to normal rules. This is all you do on your turn. This phase ends when all the tiles have been placed according to normal rules.

Between Phases
Once all the tiles have been placed, note how many completed cities, completed roads, and completed cloisters are on the map. Also note the number of completely surrounded farms on the map. Any open-ended farms along the outer edge do not count. These numbers are bonuses associated with each feature at the end of the game.

Phase 2: Ruins
On your turn, collect a tile from the outer edge of the board. If in doing so you break a completed city, road, cloister, or completely surrounded farm, score that city, road, cloister, or farm according to normal scoring rules. Continue until it would be impossible for every player to have an equal number of tiles in their collection.

Whoever has the most road segments earns the road bonus.

Whoever has the most city segments earns the city bonus.

Whoever has the most cloisters earns the cloister bonus.

Whoever has the most field segments earns the farm bonus.

Notes:
Given the mutual threat and reward for completed features, I wonder if players will actively avoid making any. It's certainly safer to make a completed feature early in phase 1 so it would take longer to reach in phase 2. Very curious.